The pop princess surprised fans in Greensboro, North Carolina by belting out a cover of the ‘90s rocker’s breakout hit during a stop on “The Circus Starring Britney Spears” Tour Saturday night.

The “Ironic” hitmaker is planning to blow the lid off her nearly five year relationship with former boyfriend Ryan Reynolds on the pages of an upcoming tell-all — much to the chagrin of ScarJo, 24, who married 32-year-old Ryan in a private ceremony in Canada last September. Alanis’ book plans could spell trouble for the very discreet Scarlett, who enjoys keeping the intimate details of her personal life off the gossip pages. She couldn’t be more disturbed by Alanis’ plans to tell-all, sources tell The National Enquirer.

Alanis and Ryan began dating in 2002. They dated for two years before becoming engaged. The couple split in 2007, leaving Alanis griefstricken, according to pals.

“Ryan was important part of Alanis’ life, and she plans to dedicate an entire chapter to her relationship with him, how devastated she was by their breakup, and how she felt when he married Scarlett,” an Enquirer spy tattles.

“Ryan will be cool with the book — he’s not especially secretive guy. Scarlett is private, and likes to think that Ryan is hers and hers alone. But there’s nothing she can do about it. Alanis is set on writing her autobiography no matter how Scarlett might feel.”

Alanis was reportedly inspired to pen her lifestory after the recent death of pop icon Michael Jackson.

“She sees how much conflicting information there is about Michael, and she doesn’t want that happen to her,” a friend explains. “She wants to lay her life out for everyone to see — even if it angers Scarlett.”

Alanis has reached an agreement with publishing giant HarperCollins, and will begin working on her memoir with a ghostwriter later this year.

Alanis Morissette will appear in a seven episode guest arc on the fifth season of the Showtime series Weeds, debuting June 8.

According to Entertainment Weekly, Alanis — who of the biggest musical acts of the 90s — has been cast as pregnant Nancy’s baby doctor, Audra Kitson.

Here’s Alanis Morissette in the official premiere of her new vid, “Not As We Are.”

Alanis Morisette sung her 1995 single “Ironic” for a massive crowd at this weekend’s Virgin Mobile V Festival, live from Chelmsford, England.

Flavors of Entanglement star Alanis Morissette performed for the ladies of The View on Wednesday.

Nineties pop icon Alanis Morissette returned to the Today Show on Tuesday to promote her latest LP Flavors of Entanglement. Flavors of Entanglement is available now.

Alanis Morissette, one of the undisputed Most Influential Entertainers of the 90s, performed songs from her new album, Flavors of Entanglement, on TODAY May 23rd.

Alanis performs her signature single “Ironic” in this video clip.

Alanis Morissette “Underneath”

Alanis Morissette is pregnant. Rumors are floating around about who the daddy might be, but last we checked, Alanis Morissette was not attached at the hip with any partner.

Stay tuned for more as it develops. Hopefully we’ll get some pictures of the baby bump soon enough.